Revolving-hook sewing-machine.



R. K. HOHMANN. REVOLVING HOOK SEWING. MACHINE. APPLIOATI6N FILED ov. 3,1910.

Patented Aug. 8, 1911.

6 SHEETS-SHEET1.

R. K. 'HOHMANN. REVOLVING HOOK SEWING MACHINE. APPLICATION FILED 11017.1910.

Patented Aug. 8, 1911. 1

5 SHEETS-SHEET 2.

R.' K. HOHMANN. REVOLVING HOOK SEWING MACHINE.

APPLIOATION FILED NOV. 3, 1910.

Patented Au 8, 1911.

5 SHEETS-SHEET 3.

R. K. HOHMANN. REVOLVING HOOK SEWING MACHINE. APPLICATION FILED NOV. 3,1910.

5 SHEETS-SHEET 4.

Patented Aug. 8, 1911.

R.'K. HOH'MANN. REVOLVING HOOK SEWING MACHINE.

APPLICATION FILED NOV. 3, 1910.

. 1,0 0,2 5 Patented Aug. 8, 1911.

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UNITED STATES PATENT came RICHARD K. HoHMANN, or SANY'DIEGO, CALIFORNIA,assrenoa or ONE-HALF 'ro PERLE M. JOHNSON, OF- SAN DIEGO, CALIFORNIA.

REVOLVING-HOOK snwin'-macnmn.

Specification of Letters Patent;

Patented Au 8,1911.

To all whom it may concern: v 1

Be it known that I, RICHARD K. HoH- warm. a citizen, of the UnitedStates, and resident of San Diego, in the county of San Diego and Stateof California, have invented certain new and useful Impro ements inRevolving-Hook Sewing-Machines, of which the following is aspecification.

This invention relates to revolving hooksewing machines and it hasparticular reference to the mechanism for holding the spool or bobbincarrying the lower thread and for passing the loop of the upper threadaround such spool or bobbin.

One .of my objects has been to make a simple and'eflicient structure bywhich the loop is passed freely around the holder for the lower bobbinor spool so that the machine may be run at a very high speed with- .outany tangling or binding of the loop evenwhere an ordinary size spool ofthread is used in the bobbin holder. I

Other objects and advantages of the 1nvention will .be apparent from theconsid-' eration of the following description in connection with theaccompanying drawings.

In the drawings,Figure 1 is a bottom plan view of a device embodying myinvention; Fig. 2 is an end v ew, parts of the sewing machine beingomitted; Fig. 3 1s a longitudinal section through the bobbin holder andassociated mechanism takenon the line- 33 of Fig. 2; Fig. 1 1s a detailperspective view of the parts of the bobbin holder separated; Fig. 5 isa'detail perspective view of one of the retaining arms for the bobbinholder; Fig. 6 is an enlarged view of the end of the rotary. shaft andattached parts; Fig. 7 is a side view of the .frame which carries theshuttle with parts a sewing machine and 2irepreeents the head removed;Fig. 8 is a detailed viewof the guide plate and finger; Fig. 9 is an endview of the casting which carries. the operat1ng parts; Fig. 10 is aperspective view of the shuttle holder showing the tension mechanism;Fig. 11 is an end view showing a modification; Fig. 12 is a side View ofthe modified construction; Fig. 13 is a top view showing detachedanother modification; Fig. 14 is a side view of, the form shown in Fig.13.

In thedrawings, 1 represents the table of carrying the needle bar andprsser foot.

ring 16 facing in the opposite The needle bar 3 and presser foot 4 areof the usual construction and the upper threa 5 may be carried andoperated in any ordinary manner, so far as the present-invention inconcerned, so long asthe take up is sufiicient to draw the loop tightafter it has passed around the bobbin holder.

Below the table 1, I make use of av rotary shaft 6 which is mounted inbearings parallel to the table, oneof these bearings being shown in Fig.3 as formed in the lug 7 on the casting 8, secured toithc table-1. Theshaft 6 has an enlarged cylindrical portion 9 immediately in front ofthe lug 7 and this cylindrical portion has in it the circumferential camgroove 10 for a purposehereafter. described. On the forward end of theshaft the outwardly inclined arms 11 and 12 are formed, and they carryat their outer ends the ring-13 This ring hason its outer surface a pin-I l-which fits in a slot 15 in the revolving hook ring 16. It is alsoprovided with screw threaded apertures which receive the screws 17 whichpass through the ring 16 to hold it in place. The shaft 6 and the partscarried by it are rotated in the usual way being driven from the drivingmechanism of the sewing. machine. The casting.8 has formed thereona ring18 surrounding the cylindrical portion 9 andarms 19, 20 extend from thisring forward and outwardly to an enlarged ring 21 which closelysurrounds the ring 13 and the revolving hook ring 16. It should beunderstood that while the ring 16 fits within the ring 21 it is not incontact with it and does not furnish a bearing for it. A frame 88 forcarrying the bobbin holder 29 is shown in Fig. 4 and it fits within thering 16 and against the edge of the ring 13, a shoulder 56 beingprovided on the ring 16 for holding it in place. This frame has abearing surface 23 semi-circular in form and oneend is sharpened at 24to form a point or hook to engage the loop of thread. "This'hookcooperates with'the hook 25 formed on the irection so that when the twohooks pass each other the. loop of thread will be caught and spreadaround the bobbin carrier as hereafter do.-

scribed. The hook-25 is formed on the edge of the ring 16 and theportion'of the ring immediately in advance of it is cut away at 26 andin addition to this the metal con-- stitutingjhe hook is cut awayontheouter I side to a certain extent at the point 27 so as in theframe.

to leave room on the outer side of this hook between it and the marginof thering for the free passage (f the thread. The frame for receivingthe bobbin holder is cut away for something over one fourth of itscircumference, and the ends of the semi-circular portion are joined bythe arm 28 which is curved at the upper end immediately below the hook 24, as shown. The cylindrical 'spool or bobbin holder 29 fits within thisframe 88, one side being immediately adjacent the arm 28, and paralleltherewith. This bobbin holder has on its outer surface the tension plate3Q and a lug 31 in line with each other, the edge of the plate and thelug being adapted to come in contact with the arm 28 when the holder isplaced in position. The opposite side of the holder has a strip 32 cuttherefrom and bent atright angles'to form an elbow 33, as shown, thiselbow resting againstthe lug 34 on the frame when the device is inposition. In line with the elbow there is also a lug 35 at the oppositeend which strikes against theshoulder36 to properly position the holderA small spring 37 projects from the shoulder 36 over the lug 35 so as toreleasably hold the parts in position. A spring 38 is also carried onthe frame and bears against the lower end of the holder 29, the curvedportion of this spring entering a small depression 73 in the'end of theholder to yieldingly retain it in position. The frame 88 has at itsupper portion the curved arms 39, 40 and the straight arms 42 and 43forming frames extending over the open upper end of the bobbin holder toserve as shields. A curved arm 44 projects from the frame 88 on its rearside so as to bear against the surface of the bobbin holder 29 when itis pushed in position. and

, it thus limits the inward movement of the holder.

Since the holder lies close to the arm 28 I cut away a portion of thatarm between the points 45, 46 so asto permit the easy passage of thethread between the holderv and the arm. In order to permit the easyremoval of the holder and at the same time lessen its weight, I providethe hole 47 in such posi ion that it may be engaged by the finger of theoperator so as to turn the holder and release it from the spring 37.

The holder is provided with a central shaft,

50 and from that point it is carried beneath the: lowenend of. thetension plate 51 tlu'jt ugh the slot into the eye 52, and from there itpasses over the end of the holder around the roller 53 which is looselymounted in the lower end of the hollow shaft 48.

The thread is wrapped one full'turn around this roller and is thenbrought back over the edge of the holder, thus making almost two turnsaround the roller, and it is then carried up through the eye 54 in theupper end of the tension plate. This roller with the other partsmentioned constitutes an autoinatic tension device which always keepsthe thread; tight while permitting it to be withdrawn as desired, and itis equally effective without regard to the 'size of the thread which isused.

It will be observed by reference to Fig. 4 that a portion of the forwardedge of the revolving hook ring 16 between the point 55 and the hook 25is cut away to allow for the passage of the thread along this portion ofthe ring. The ring itself has on its inner surface a shoulder 56whichfits against the ring 13, thus holding the parts in position andholding the bearing surface 23 of the frame 88 in place. The ring 13 andthe revolving'hook ring 16 of course revolve with the revolving shaft-J6, and they would by arms 57, 58 of the particular form shown in Fig. 5,these arms being mounted in slots in the arms 19 and 20 of the casting8. These arms have at their rear ends a reducedpon tion 59 which passesthrough the opening 60 so as to properly guide the arms in their forwardand backward motion. .Each arm has at its forward end an inwardlyprojecting portion 61 which may be formed with or attached to the arm inany suitable man ner, it being shown in Fig. 5 as attached by a screw.This projection has a pin 62, extending inwardly in the line of themotion of the arm and adapted to enter an opening 63 in the frame 88which carries the spool holder. The arms 57 and 58am alike, and whilethe finger on one enters the opening 63, the finger on the other entersopening 64.

Each arm has near its rear end a roller working in the cam groove 10 inthe cylindrical portion 9 of the rotary shaft, and the shape of the camgroove and the position of the arms around its surface are such that oneof the pins 62 will always be held in the the thread reaches that arm.By this means the thread holder is prevented from'rotating and at thesame time no obstruction whatever is presented to the free passage ofthe loop of thread around it. In order to prevent any accidentalengagement by the loop of thread with the end of the pin 62, I secure tothe face of the ring 21 a plate 66 by means of screws passing throughthe openings 67, 68 and 69. On this plate I place a curved finger 70which is placed immediately adjacent the end of the arm 57 so that itwill guide and retain the loop so as to prevent it from accidentallyextending out so as to catch on the pin 62. The outer surface of theplate is cut away at 71 and 72 to permit the passage of the two arms.

The purpose of extending the plate 66 around the ring 21 over the arms57 and 58 is to serve. as a retaining member to guide those arms attheir forward ends and prevent them from coming in contact with therevolving hook 16. The curved finger 70 is not absolutely necessary, butI find that it assists in the free operation of the-device when placedadjacent the end of that arm which is reached last by the loop of threadas it passes around the holder. At this point the loop is being releasedand drawn up and is therefore more likely to extend outwardly from theholder.

It will be observed from the above description of the structure that thecylin drical holder 29 is adapted to contain either an ordinary spool ofthread or a bobbin, and that the spool may be easily and quicklyinserted through the open end fitting on the shaft- 48. The holderitself may be easily and quickly secured in'or removed from the frame 23in operative position in the ma chine. It is simply snapped intoposition against the slight tension of springs 37, 38 and is removed bya slight pull by the finger engaged in the opening 47.

In operation a loop of thread formed by the descent of the needle isengaged by'the hook'25 and is carried forward by that hook past thestationary hook 24, and is engaged thereby. One side of the loop willlie over the top of the hook 25 extending along the cut-away portion atthe point 27 until the hook moves some distance and reaches its lowerposition when it will travel up' over the guard arm 39 and the strip 82and thus pass over the holder 29. The other end of the loop passes upthe guard aria -10 and the arm 4-1 and thus guided over the holder.After the loop has traveled something over half the revolution of thehook it is released and may be drawn tight by the take up. As the hook25 approaches each arm 57, 58 that arm is moved forward by the action ofthe cam groove 10 so that its pin is disengaged from the frame'88 so astopermit the free passage of the thread by that arm. The arm is movedback into position as soon as the thread passes, andbefore it-reachesthe next arm.

while I have. shown and described one form of device embodying myinvention it will be understood that its principles are applicable toother forms and that I do not limit myself to the precise constructionshown. In the particular form hown how ever I have found that themachine may be successfully run at a speed of two thousand revolutionsper minute. Instead of using the longitudinally sliding arms 57 and 58for holding the shuttle frame against rotation, I may make use of themodified construction shown in Figs. 11. and

'12. In this instance a shaft 90 is rotatively 8 mounted in the casting8 parallel with the direction of the rotary shaft 6 and at the rear endof this shaft there is secured a forked arm 74 which embraces the cam 75which rotates with the rotary shaft. On

the opposite end of the shaft 90 is secured a part having two arms 7 6,77, each arm having at its-end a finger or lug forthe purpose hereafterdescribed. The frame 88 instead of having holes in its side forengagement by the fingers, as shown in Figs. 4 and 7, is provided withafiange 7 8 extending beyond the edge of the rotary hook ringrand thisflange has the radial holes 79 89, to reoeive the fingers on the armsand 77. 1

It will be noted that the arms 76 and 77'aire rocked by means of the cam75 which engages the forked arm and the fingeron one arm will enter one.of the holes in the frame before the finger on the other arm is entirelywithdrawn so that the frame is atall times heldagainst rotation. Theshape oft-he cam and the consequentoscillation of the arms is such thatthe fingersare withdrawn just at the time that the loop of threadreaches that point in passing around the holder.

In Figs. 13 and 14 I have shown tii'igers 81, 82, which are adapted tbenter openings- -in the face of the frame corresponding to 63 and 64:shown in Fig. 7, butj-instead. of

sliding these fingers are mounted'upon an oscillating frame 83 pivotedat 84. ,One end of this frame is the upwardly: e ltcnding forked arms85, 86, which are engaged and operated by a cam surface '87 which maybe.continuously rotated with the rotaryshaft.

This cam surface oscillates the frame 83, thus withdrawing the fingers81 and .82 succ'essively and the timing is such that they will bewithdrawn as the thread approaches them. I

Having thus described the invention, what is claimed is: v

1. Ina device of the classdescribed, the combination with a rotaryshaft, of a reedge, and a practically continuous bearing groove on itsinterior, of a frame constituting a bobbincarrier having a bearing rimfitting in said groove throughout more than half of its circumferenceand extending I through the bottom quarter of the circumference of saidgroove, a plurality ofineans' for alternately engaging said'franiewithin about one quarter of its circumference atthe bottom.

2. In a device of the class described, the combination with a rotaryshaft, of a revolving ring, having a hook formed on one edge',-and apractically continuous bearing groove on its interior, of a bobbinholder having a bearing. rim fitting in said groove throughout more thanhalf'of the circumference, and being cut away on one side from a pointnear the bottom to the top and'ineans for completely taking up thethread at each revolution of the hook the said means constructed tooperate as the thread reaches said cut away portion.

3. In a device of the class described, the combination with a revolvinghook having a practically continuous interior circular cut away portion.

4. In a device'of the class described,the combination with a revolvinghook having a practically continuous interior circular bearing surface,of a bobbin carrier having a rim fitting in said bearing surface cutaway on one side from the top to a point near the bottom but leavingabearing-surface throughout the bottom quarter, means for securing aspool or bobbin in said carrier with'its axis centrally of said bearingsurface but at a slight inclination to the vertical, and means forpreventing the rotation of said carrier while permitting the passage ofa loop of thread around it and means for completely taking up the threadat each revolution of the hook the said means constructed to operate asthe thread reaches said cut away portion.

5. In a device of the class described, the coml'iination with arevolving hook having a practically continuous interior circularbearing, of a bobbin carrier having a rim fitting in said bearing,saidrim being cut away circumferentially from a point at the top to apoint at the side, and, a plurality of pins adapted to engage saidcarrier within about one quarter of the circumference at the bottom, andmeans for operating said pins alternately whereby a' loop of thread maypass freely.

' 6. In a device bf the class described, the combination with a bobbinholder having a bearing rim in the arc of a circle, of means for passinga loop of thread around said holder, a plurality of engaging means forholdingsaid bobbinagainst rotation within about one-quarter of thecircumference at the bottom, means for disengaging said holding meansalternately whereby the loop may pass freely around the holder, andmeans for completely drawing up said loop to form the stitch beforepassing a second loop around the holder.

7. In a device of the class described, the combination with a bobbinholder, of a rotary shaft in line therewith, divergent arms on the endof said shaft carrying a revolving hook ring at their outer ends, aframe closely surrounding said arms and ring the said frame beingprovided 011 .its inner side with two separated longitudinal slots,

7 arms slidably mounted in isaidslots having their outer ends extendedaround said ring and back toward the same, and cam slot connectionbetween the inner-ends of said slidably mounted arms and rotary shaft.

8. In a device of the class described, the combination with a revolvingring having a hook formed onone edge and a continuyieldingly holdingsaid bobbin holder in place, and means for preventing the rotation ofsaid frame in said bearing groove and for holding it with the continuousportion'. of its bearing throughout the lower quarter of thecircumference, I

9. In a device of the class described, the combination with'a bobbinholder, of a rotary shaft in line therewith, divergent arms on the endof said shaft carrying a revolving-hook ring at their outer ends, aframe closely surrounding said arms and ring, the

said frame being provided on its inner side With two separatedlongitudinal slots, arms slidably mounted in said slots having theirouter ends extended around said ring and back toward the same, cam slotconnection between the inner ends of said slidably mounted arms androtary shaft. and a guard ing rim, of a hook on one end of said rim, across arm connecting the ends of said rim, a cylindrical bobbin holderfitting in said frame along said arm and having aprojecting partlongitudinally thereof abutting against said arm to properly positionsaid holder,-co6perating stops on said frame and on the side of saidholder opposite said projecting part, and spring catches between saidframe and-holder to retain it in position.

11. In a device of the class described, the combination with asemi-circular ring like supporting frame having an exterior hearing rim,of a hook on one end of said rim, a cross arm connecting the ends ofsaid rim, a cylindrical bobbin holder fitting in said frame along saidarm and having a projecting part longitudinally thereof abutting againstsaid arm to properly position said holder, codperat-ing stops on saidframe and on the side of said holder opposite said projecting part, andspring catches between said frame and holder to retain it'in position,the said bobbin holder-being centrally arranged in said frame with itsaxis at right angles to the axis of said bearing rim.

- 12. In a device of g the class described, the combination with asemi-circular ring like supportingframe having an exterior hearing rim,of a hook on one end of'said rim, a cross arm connecting the ends ofsaid rim, the said cross arm forming one side of an opening in saidframe adapted to receive a spool holder, stops on said frame adapted tocoiiperate with said holder to retain it in position along said crossarm, and guards having' semi-circular outer margins extending at one endfrom said frame over the end of said opening. a

13. In a device of the class described, the combination with asemi-circular ring-like supporting frame having an exterior bearing rim,of a hook on one end of said rim, a cross arm connecting the ends ofsaid rim, the arm at the'end adjacent the hook-being extended beneaththe same in the direction in which it points and then across to theother end of the frame forming an opening therein adapted to receive abobbin holder rectangular in longitudinal section, and

guards having semi-circular outer margins copiesioi this patent may beobtained for five cents each, by addressing the Commissioner of Patents.

and open at one end, of a post therein-adapted to receive an-ordinaryspool or bobbin, a

tension plate extending longitudinally of said holder on one side, stopsin line on the opposite side, a frame having an opening,

provided with marginal stops adapted to receive said holder, the saidmarginal stops therein coiiperating' with said tension plate andstops'on the holder to limit the insertion of the holder, and yieldingmeans for retaining the holder in place.

15. The combination with a cylindrical bobbin holder having a threadslot therein and open at one end, of a post therein adapted to receivean ordinary spool or bobbin, a tension plate extending longitudinally ofsaid holder on one side, stops in line on the opposite side,.a framehavingan opening provided with stops adapted to receive said holder, thesaid stops therein cooperating with said tension plate and stops on theholder to limit the insertion of the holder, yielding means forretainingthe holder in place, and guards on the frame extending over the open endof said holder.

16. In a sewing machine, thecombination with a needle and operatingmechanism to form a loop of thread, of. a revolving ring having a hookto engage said loop and a practically continuous circular bearing on itsinterior, a bobbin holder having a bearing fitting said first mentionedbearing and being cut away circumferentially from the top to a pointnear the bottom, ahook on said holder facing said cut away portion atthe top coiiperating with the hook on said ring to spread the loop,means at the bottom portion of said holder to prevent its rotation, andmeans for completely taking uthe thread at each revolution of the. hoothe said means constructed to operate as the thread reaches said cutaway portion.

In testimony whereof I affix my signature in presence of two witnesses.

RICHARD K. HOHMANN.

Witnesses ARTHUR L. BRYANT, JOHN M. Coir.

Washington, D. C.

